Another stream of works adopt an iterative framework by updating the queries. [1]} iteratively generate new queries by selecting a span from the question and retrieved evidence while [2]}, [3]}, [4]} directly append retrieved evidence to the query.
Compared with these works,
we introduce two novel query updating techniques, hard masking and soft masking, together with an evidence integration module to avoid too much
overlap between evidence and to dynamically determine the number of required evidence sentences.
